Device for comparing luminous areas.



PATENTBD MAR. 20, 1906.

N6. 815,865.- W. DA. RYAN; I

DEVICE FOR GOMPARIHG-LUMINOUS ARBAS.

APPLICATION FILED JULY 28. 1904.

2 SHEETS-SHEET 1.

WITNESSES:

lNVENTOR.

'A. RYAN.

WALTER w gm ' PATENTBD MAR. 20, 1906.

- 3W. D'A. RYAN; I '--D,EVIGE 'FORGOMPARING LUMINOUS AREAS.

APPIQIQATION FILED JULY 28. 1904.

NVENTOR.

WALTER DA. RYAN;

A ATT'Y.

UNITED STATES PATENT. oFFroE.

WALTER DA.' RYAN, OF LYNN, MASSACHUSETTS, ASSIGNOR TO GENERALELEOTRIOOOMPANY, A. CORPORATION OF NEW YORK.

DEVICE FOR COMPARING LUMINOUS AREAS.

are detail cross-sections.

Specification of Letters Patent.

- Patented March 20, 1906.

To all whom it may concern/.- v

Be it known that I, WALTER DA. RYAN, a subject of theKing of GreatBritain, residing at Lynn, county of Essex, State of Massachusetts, haveinvented certain new and use ful Improvements in Devices for ComparingLuminous Areas, of which the following is a specification.

This invention relates to photometry; and its object is to enablean'observer to compare the light emitted from two or more sources withspecial reference to the color effects.

It consists, as its name'implies, in an apparatus arranged to throw upona screen areas of illumination from different luminous obj ects, so thattheir difference in color may be readily seen and compared.

The preferred form of apparatus is hereinafter shown and described, andthe novel features are pointed'out in the claims. r

In the accompanying drawings, Figure 1 is a perspective view of anapparatus embodying my invention. Fig. 2 is a side elevation, partlybroken away and partly in section, on the line 2 2, Fig. 3. Fig. 3 is arear sectional elevation on the line 3 3, Fig. 2; Fig. 4

shows the field of view as thrown on a screen by the apparatusillustrated. Figs. 5 and 6 Fig. 7 is a front elevation of a portion of.a ventilator, and Fig. 8 is a cross-section of the same.

The parachromoscope or multiple projector herein shown and described isarranged to compare four different lightsas, for instance,

an arc-lamp, a Welsbach gas-burner, a Nernst lamp, andan incandescentlamp; but it is evident that other lamps or burners may be. substitutedfor any of these, if desired.

The body of the apparatus shown has four compartments arranged in twotiers of two each. Each compartment is preferably a separate box 1, ofwhich one side 2 is hinged. Near the bottom of the back of each box isan inlet-ventilator, preferably a row of holes 3, protected by a screen4, containing holes 5- out of line with theholes 3. Inside the boxheated air. These lamps are each supported by a slide 10, movable incleats 11 at the top of the box and running from front to rear.

A rod 12 extends from each slide out through.

the back of the box.

The arc-lamp 13 is hung from a ring 14, supported on posts 15, set insockets on a base 16, fastened on top of a slide 17, which can bemovedback and forth on top of the.

. opening. The inner edge of the base 16 projects over these holes,being spaced above them bythe thickness of the slide. These holes thusafford means for the heated air to escape from the box up through thecenter of the base 16.- An annular flange 22 is secured to the lower endof the tube 19 and has a downwardly-curved edge fitting over the cap ofthe lamp-globe, so that no light can escape through the top of the box.The top of the box has an opening, through which the tube depends, largeenough to permit the slide and tube to be moved back and forth aconsiderable distance.

The Welsbach burner 23 is mounted on a gas-pipe 24, which can be slidback and forth through the'back of the box and is supported on a slide25 inside the box. Above this burner is a ventilator comprising anupright sheet metal cylinder 26, surmounted by a dome 27, supported onbrackets 28. The edge of the dome comes down below the top of thecylinder, having an annular space all around for the escape of theheated air and products of combustion without letting out anylight-rays.

In the front of each box is an opening 29, leading into a projector 30,which is provided with specially-ground lenses without balsam in orderto avoid the danger of selective absorption. I The projector has aniris-shutter contained in the enlarged casing shown on the end of theprojector. The axes of the several projectors are non-convergent, sothat the field of light thrown by each one does not overlap the others.

The operation of the instrument is as follows: The various sources oflight are ad justed back and forth, and the irisshutters are manipulateduntil the luminous intensity of all the lights is brought to the samevalue, preferably at about the D line of the spectrum. The four disks oflight, preferably about fifteen inches in diameter, are thrown on ascreensay ten feet from the instrument. The disk 31 from the arc-lampappears White, the disk 32 from the Welsbach burner green or greenishyellow, the disk 33 from the N ernst lamp pale yellow, and the disk 34from the incandescent lamp a deeper yellow. By placing a sheet ofcolored fabric so as to include all the disks the relative effects ofthe various lights are clearly shown. A plaid material of certain colorsshows that different colors under different lights undergo radicalchanges. The instrument is therefore of especial value for instance, indem onstrating to merchants dealing in dress goods how their waresappear under the various kinds of lights. If it is desired to study thelights spectroscopically, a prism attachment 35 can be placed on eachprojector, so that the four spectra are thrown on the screen side byside, and the composition of the lights can very readily be compared.

What I claim as new, and desire to secure by Letters Patent of theUnited States, is

1. An instrument for comparing the relative effects of different sourcesof light, comprising a separate compartment for each light and aprojector extending therefrom, said projectors permanently fixed withtheir axes non-convergent, and the light source in each compartmentbeing of a different kind from those in the other compartments.

2. An instrument for comparing the relative efiects of different sourcesof light, comprising a separate compartment for each ight,permanently-fixed non-convergent projectors extending therefrom, ashutter on said projector, and means for adjusting the position of thelight in each compartment the light source in each compartment being ofa different kind from those in the other compartments.

3. An instrument for comparing the rela tive effects of differentsources of light, comprising a separate compartment for each light,permanently-fixed non-convergent proj ectors extending from the front ofthe same, a slide movable back and forth in each compartment, and alight source mounted on said slide, said light sources being ofdiflerent kinds.

{L An instrument for comparing the relative effects of different sourcesof light, comprising a separate compartment for each light, permanentlylixed non-convergent projectors extending from the front ofthe same, a slide in each compartment for supporting the light, andventilators at the lower and upper parts of each compartment the lightsource in each compartment being of a different kind from those in theother compartments.

5. In a device for comparing luminous areas, the combination with a boxhaving a projector .on its front, and means for adjustably supporting alight, of a ventilator comprising a row of holes in the wall of the box,an external screen having holes not registering with those in the box,and internal overlapping baffle-plates.

6. In a device for comparing luminous areas, the combination with a boxhaving a projector on its front, and an opening in its top, of a slideon the top of the box containing an opening, an arc-lamp supported onsaid slide and depending into the box, and a ventilator concentric withthe opening in the slide.

7. Ina device forcomparing luminous areas, the combination with a boxhaving a projector on its front and an opening in its top, of a slidecovering said opening and containing an opening itself, an annularbase-plate concentric with said slide-opening, posts on said plate andan annular lamp-support on said posts.

8. In a device for comparing luminous areas, the combination with a boxhaving a projector on its front and an opening in its top, of a slidecovering said opening, an annular plate concentric with saidslide-opening and extending partly over the same, a short tube having aflange secured to the under side of the slide and containing a number ofholes, a flange secured to the lower end of said tube, and an arc-lampsupported on said plate and depending through said tube.

9. In a device for comparing luminous areas, the combination with aplurality of compartments each having a projector rigidly mount ed onits front, the axes of said projectors being non-convergent, of means inone compartment for supporting an arc-lamp, means in another compartmentfor supporting an incandescent lamp, and means in another compartmentfor supporting a gas-burner device.

In witness whereof I hereunto set my hand this 25th day of July, 1.904.

WALTER DA. RYAN.

Witnesses DUGALD MoK. MoKILLoP, JOHN A. McMANUs.

